Functions including provision of visual barriers, physical separation, privacy, protection from strong sunlight, and decoration have been realized with curtain materials for many centuries. Apparatus realizing these purposes has been known variously by terms such as curtains, drapes, blinds, and shades, and has been implemented in numerous configurations to combine functions and provide desired appearance. An enduring style, the so-called Roman shade, uses a fabric that can be drawn away from a window, for example, commonly using two or more cords to lift the fabric, and forming the lifted fabric into tiers—that is, continuous panels extending the width of the shade, with a portion such as a bottom edge of each tier commonly visible after the Roman shade is lifted.
The fabric forming a Roman shade is preferably readily flexed or articulated to form the tiers, and is preferably caused to be somewhat rigid at least in part along each tier. In some embodiments, it is known to use small, comparatively resilient strakes, that is, pieces of materials such as reeds, split bamboo, dowels, or modern substitutes, which may be hollow or solid plastic elements such as extruded rods or tubes, to form the horizontal elements of the tiered fabric. In such embodiments, the strakes may be held together in parallel to form a surface using flexible materials such as natural or synthetic fiber threads woven around the strakes. These embodiments may be termed non-isotropic, since bending properties are necessarily different along the axes parallel to and at right angles to the strakes. In other embodiments, a substantially isotropic shade fabric may be reinforced at the locations forming the top edges of the tiers using battens, that is, relatively rigid slats or rods extending roughly the width of the shade and fastened to the shade fabric by a method such as inserting the battens into pockets formed into the fabric.
Fabrics of the types described may block most sunlight, may be highly decorative and/or durable, and may function as somewhat effective visual screens. However, in many instances, the fabrics allow some direct passage of sunlight and allow items on one side of the shade to be viewed from the other side. Some fabrics may likewise be susceptible to deterioration such as weakening or embrittlement of fibers or fading of colors caused by exposure to light. These characteristics may be undesirable in at least some applications.
A second layer of fabric, termed a liner, is sometimes added to a Roman shade to address at least some of the needs described. Liners according to known practices are custom-fitted to a specific size and design of shade, with attachment between the layers developed ad-hoc and frequently requiring cutting and sewing merely to remove the liner for washing, for example.
Accordingly, there is a need in the art for a second layer of fabric in the form of a liner for a Roman shade, removably attached to the shade, to increase blockage of view and blockage of solar irradiance when compared to conventional designs, while retaining utility largely equivalent to that of a Roman shade of conventional design. The need extends to a universal liner—that is, one readily attached to and removed from any available Roman shade of comparable size without experimentation or adaptation.